Problems with OS::Nova::Server metadata property and complex values

[Lars Kellogg-Stedman]

It is possible to set the "metadata" property of an OS::Nova::Server instance to a complex value. For example:

instance0:
  type: OS::Nova::Server
  metadata:
    internal_ip: {get_attr: [instance0_eth1, fixed_ips]}

While this does not result in any errors, the value available in the "meta" key of the metadata service (http://169.254.169.254/openstack/latest/meta_data.json) is the result of a Python "str()" on the value:

  $ curl http://169.254.169.254/openstack/latest/meta_data.json | jq .meta
  {
    "internal_ip": "[{u'subnet_id': u'20bb4a78-876a-465a-bfe8-868e800e3c0c', u'ip_address': u'10.0.0.2'}]",
  }

It seems like heat should do one of two things:

(a) Refuse to create the stack if a metadata key is set to a non-string value, or
(b) Serialize complex values using, e.g., JSON

[Steve Baker (steve-stevebaker)]

I assume you mean the metadata property:

instance0:
  type: OS::Nova::Server
  properties:
    metadata:
      internal_ip: {get_attr: [instance0_eth1, fixed_ips]}

Serialising complex values to json seems reasonable. Feel free to provide a fix which implements and documents this.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/70045

[Lars Kellogg-Stedman (larsks)]

The referenced change serializes all non-string values to JSON when they are passed to nova. I have updated test_server_update_nova_metadata (and _with_delete) to check this, but I did not otherwise see a good location for documentation in this repository. If this patch or similar is accepted, it seems as if the rigth place for documentation would be http://docs.openstack.org/developer/heat/template_guide/openstack.html#OS::Nova::Server (and I'm happy to take care of submitting a patch for that if necessary).

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/70045
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=3e3fc3e1ff0ce4edce9f432fe31d2d8e45082681
Submitter: Jenkins
Branch: master

commit 3e3fc3e1ff0ce4edce9f432fe31d2d8e45082681
Author: Lars Kellogg-Stedman <email address hidden>
Date: Wed Jan 29 22:05:47 2014 -0500

    serialize non-string nova metadata

    This patches ensures that non-string metadata values passed to Nova
    are JSON-encoded. This permits setting metadata to complex values,
    such as:

        instance0:
          type: OS::Nova::Server
          properties:
            metadata:
              internal_ip: {get_attr: [instance0_eth1, fixed_ips]}

    Change-Id: I1a943876d805dce731771b18a39d0c78f617264a
    Closes-Bug: 1274155